The mobile telephone industry has been associated with tremendous growth over the last several years. For instance, in the recent past, mobile telephones were only available to those of highest economic status due to service costs and costs associated with mobile phones. Moreover, network coverage was not extensive enough to enable robust service. In particular, only areas associated with dense population were provided with extensive wireless network coverage. Still further, the mobile phones that could utilize the networks to communicate were quite bulky, causing portation of the phone over any significant distance to be difficult at best. In more detail, antennas associated with these phones could be over a foot in length, thus making it difficult to utilize the phones in automobiles or other congested areas.
In contrast, today's portable phones (and other portable devices) can be utilized as full-service computing machines. For example, many of the most recent and advanced mobile phones can be associated with word processing software, accounting software, and various other types of software. Furthermore, network coverage has expanded to cover millions, if not billions, of users. Additionally, mobile phones have decreased in both size and cost. Specifically, modern mobile phones are often small enough to slip into an individual's pocket without discomforting the individual. Furthermore, many mobile network service providers offer phones at extremely low cost to customers who contract for service with such providers.
Advances in technology relating to mobile devices in general, and mobile phones in particular, contine to occur. For example, recently mobile telephones have been designed to communicate over disparate networks and/or between licensed and unlicensed spectra. In more detail, a dual mode handset can connect to a cellular network to effectuate communications between a user of the mobile phone and another phone device, and can further connect via WiFi to a wireless local access network (LAN) and thereafter utilize the Voice over Internet Protocol (VoIP) to effectuate communication between users. Use of VoIP is often desirable to users as it is associated with less cost than employing a cellular network. In fact, some users may consider phone calls made over VoIP (or other IP-based network) completely free, despite the fact that they pay for Internet service.
Implementation of this dual mode service is due at least in part to the Third Generation Partnership Project (3GPP), which have created specifications that define a mechanism that provides signal interity for session initial protocol (SIP) signals between an IP multimedia subsystem (IMS) (P-SCCF) and user equiment (UE) (e.g., a mobile phone, a personal digital assistant, . . . ). This integrity prevents identity spoofing, man-in-the-middle attacks, and the like. The IMS represents a 3GPP and 3GPP2 effort to define an all-IP-based wireless network as a replacement for the various voice, data, signaling, and control network elements currently in existence. Furthermore, the IMS enables support for IP multimedia applications within the Universal Mobile Telecommunications System (UMTS). The UMTS is a 3G broadband packet-based transmission of text, ditized voice, video, and multimedia that offers a consistent set of services to mobile computer and phone users regardless of their physical location.
The telecom industry is currently shifting towards all IP-systems, thereby rendering dual mode service handsets an important tool (as they are compatible with existing cellular systems and emerging IP-systems). This shift is driven by desires to reduce costs and create new streams of revenue while protecting an operator business model. IMS is a new service domain that facilitates this shift by enabling convergence of data, speech, and network techonology over an IP-based infrastructure. For users, IMS-based services enable transmittal and receipt of various data at significantly reduced cost, including voice, text, pictures, video, and/or any combination thereof in a highly personalized and secure manner. In summary, IMS is designed to bridge the gap between existing, traditional telecommunications technology and Internet technology that increased bandwidth does not provide.
As stated above, these emerging IP-based technologies have created demand for dual mode services, and thus for dual mode handsets. Using this technology, users can employ WiFi to effectuate voice calls, transmission of data, and the like. In more detail, a user can connect to a LAN by way of WiFi. Upon such connection, users can employ services offered by their service provider.